I've just added some Comments (some just personal opinion) and my Modders Knowledge to some scenarios. I didn't answer it all, as some of the points are points only a mod's author/visionary (I believe) should be the one to have the say in.
VSR gives animal people grasping tails
This adds a lot of changes to the base files and I'm concerned about side effects, such as mittens going on tails and such. I also have a bit of trouble seeing how legless animal people can use their tails to attack or hold things, seeing as they're currently using it for balance.
if the tail lacks a LEFT or RIGHT token it should be fine, because crafted gloves have "handedness" so they shouldn't be putting a glove on it. If anything creatures that use it for STANCE will probably have socks and boots
VSR makes animal people dwarf sized
I actually prefer the flavor of vanilla, to be honest. I see Revised as being about look and feel first of all, bug-fixing second, and gameplay tweaks a distant third. This leaned a little too far into "gameplay tweaks" territory for my comfort.
I feel any "small" creature should be between 50k and 60k Kobold/Goblin sizes. But mid sized creatures would be 70k Human sized and maybe 80 to 90k for the "large" creatures, but I could see that being a lot of work to go through and adjust those sizes for those animal-men
VSR gives worm people utterances and buffs them
See the comments about gameplay tweaks. I did integrate the skill improvements Warlord255 added for all(?) animal people, but worm people were buffed above and beyond this. I'm on the fence, so I didn't add it. I'm not sure off-hand what all the UTTERANCES tag does, so I erred on the side of caution.
Only commenting on the UTTERANCES portion. UTTERANCES from testing from another modder, and validated by me and others. Just makes it so the creature will use RNG gibberish language, it was previously believed that it would incite war with them if they were a civ, but that was due to not having CAN_SPEAK.
Also you can combine CAN_SPEAK and UTTERANCES to have a speaking race that just doesn't use a translation and names everything in gibberish.
VSR rework crows and magpies as proper creatures, not vermin
Why can't they be vermin? I can see why it's inconsistent with other creatures, though. The new Modest Mod thread has at least one person suggesting that more creatures be made vermin. It means quite a few changes from vanilla either way though, so I'm wary of it.
Currently I'm going off of bodysize to make something VERMIN or not, because somethings are like 30k and vermin but then something that is 20k is not? doesn't make sense. Also they're so small they don't even yield much in butchering so being a full creature is more of a joke. However doing this as you've stated is quite a change to vanilla, I just wanted to add my 2 cents (more creatures should be vermin)
VSR makes sharks and carp crazed
I'm concerned I've already gone too far in the "make the game arbitrarily harder" direction, with all the CURIOUS item stealing tags everywhere and the new harder farming changes I integrated. This doesn't seem particularly realistic either, to be honest.
having them CRAZED would just mean they'd attack anything that isn't a SHARK or CARP. Basically making them an apex predator. Ofcourse that means anything going into the ocean or rivers/lakes (undead, wild, civilized) is gonna get attacked by these things.
Carp already enjoy attacking people, this would just make them more hostile than badgers.
VSR gives cave_adapted to underground creatures
Interesting change. I was on the fence about it. I ended up not adding this because it needed quite a few changes and I didn't think it would come out in gameplay enough. I also want to do proper gameplay testing for this release and to be honest I didn't feel like adding this to my testing to-do list.
Personal Opinion here, if they're already underground creatures they should already have a perfect LOW_LIGHT_VISION but maybe a lower VIEWRANGE (under default 20) however be able to SENSE or SMELL really good. However creatures like Dwarves tend to be a mix of underground yet surface faring creatures, so being able to "cave_adapt" makes sense in their context, and the vomiting from one that's adapted to the underworld.
VSR removes vermin attacks because they don't attack correctly
I've never noticed this coming out in-game as a bug? I'm wary of including fixes for things that don't actually affect my gameplay, but I might be wrong about this one.
I've never seen this as an issue either. The worse case could be when an Animal_Man CV is applied, but I'm sure the CV removes all ATTACK tokens anyways, then re-adds attacks after.